An Unusual Case of Talon Cusp on Geminated Tooth

Home , Cusp (anatomy), Dental papilla, Talon cusp

C LINICAL P RACTICE

• Faiez N. Hattab, BDS, PhD • • Abdalla M. Hazza’a, BDS, MScD, DDSc •

Abstract A rare case of talon cusp on geminated permanent central incisor is described. These developmental anomalies cause clinical problems including unsightly dental appearance, occlusal interference, displacement of the affected tooth, attrition, periodontopathy, irritation of the tongue, loss of space and malocclusion. Clinical and radiographic characteristics of these anomalies and modes of treatment are presented. Recognition of this condition and early diagnosis are important to avoid complications.

MeSH Key Words: case report; child; incisor/abnormalities; tooth crown/abnormalities

he talon cusp, or dens evaginatus of anterior teeth, stage of tooth development. It may occur as a result of is a relatively rare developmental anomaly charac- outward folding of inner enamel epithelial cells and tran- T terized by the presence of an accessory cusplike sient focal hyperplasia of the peripheral cells of mesenchy- structure projecting from the cingulum area or cemento- mal dental papilla. The talon cusp can occur as an isolated enamel junction of the maxillary or mandibular anterior finding or in association with other dental anomalies such teeth in both the primary and permanent dentition. This as peg-shaped lateral incisor, agenesis or impacted canines, anomalous structure is composed of normal enamel and mesiodens, complex odontomes, megadont, dens evagina- dentin and either has varying extensions of pulp tissue into tus of posterior teeth, shovel-shaped incisors, dens invagi- it or is devoid of a pulp horn.1-4 In its typical shape, the natus and exaggarated Carabelli cusp.1-5 The talon cusp has anomaly resembles an eagle’s talon,2 but it could also not been reported as an integral part of any specific present as pyramidal, conical or teat-like.1-5 syndrome, although it appears to be more prevalent in The prevalence of talon cusp varies considerably among patients with Rubinstein-Taybi syndrome, Mohr syndrome, populations, ranging from 0.06% to 7.7%.6,7 In addition to Sturge-Weber syndrome, incontinentia pigmenti achromi- the ethnic variation, the lack of precise criteria to classify an ans and Ellis-van Creveld syndrome.1,8,10 accessory cusp as a “talon” has contributed to the extensive Geminated teeth are developmental anomalies of tooth variations in prevalence.1 The permanent dentition is shape that arise from an abortive attempt by a single tooth affected more frequently than the primary dentition, and bud to divide, resulting in a bifid crown. They are found the anomaly is more common in males than in more frequently in the primary than in the permanent females.1,4,5,8,9 Almost 92% of the affected (taloned) teeth dentition, with a prevalence of approximately 1% and 0.1% in the permanent dentition have been found in the maxilla, respectively in Caucasian groups.11-13 There seems to be no with the lateral incisors being the most frequently involved gender differences in occurrence. Gemination, however, is (55%) followed by the central incisors (36%) and the most often seen in the maxillary primary incisors and the canines.1,9 canines. The etiology of talon cusp is not well understood, but The etiology of geminated teeth remains unknown. appears to have both genetic and environmental compo- Spouge suggests that the condition may result from trauma nents.1,4 Similar to other abnormalities of tooth shape, to the developing tooth bud.14 Evidence from case history talon cusp originates during the morpho-differentiation studies suggests that the anomaly exhibits a hereditary

Journal of the Canadian Dental Association May 2001, Vol. 67, No. 5 263 Hattab, Hazza’a

tendency, similar to that affecting the dental lamina and toward the incisal edge. The talon cusp was outlined by 2 resulting in hyperdontia.15 The mode of inheritance is distinct white lines converging from the cervical area of the probably either autosomal recessive or dominant with very affected tooth toward the incisal edge. Pulp extension could little penetrance.12 It appears that gemination is caused by be traced radiographically to the middle of the cusp. The complex interactions among a variety of genetic and envi- geminated-taloned tooth had a single enlarged pulp cham- ronmental factors. ber, one root and bifid crown appearance. An occlusal radio- Talon cusp on geminated tooth is a very rare finding. A graph revealed the presence of lateral incisors, with the review of the literature revealed only 2 previous reports.16,17 affected tooth impeding the eruption of the adjacent lateral The purposes of this article are to present a case of talon incisor. Based upon clinical and radiographic findings, a cusp on geminated maxillary central that caused clinical diagnosis of talon cusp on geminated tooth was made. problems and to describe treatment modalities. After diagnosis, it was decided to extract the mobile left Case Report primary lateral incisor, which, with the anomalous central incisor, formed a site for food impaction and plaque accu- A 9-year-old Jordanian-Arab boy presented to the dental mulation (Fig. 2). Approximately 1 mm of the talon cusp clinic complaining of large, unsightly maxillary central was ground off, without exposing the pulp, to eliminate the incisors, irritation to the tongue, incising problems, food source of tongue irritation and occlusal interference. The impaction and bleeding gums. ground surface was treated with fluoride varnish (Duraphat, The patient was the sixth of 7 siblings of parents with no Woelm Pharma Co., Eschwege, Germany), as a desensitiz- history of consanguinity. No other member of the family was affected by similar dental anomalies. The patient ing agent. The mesial and distal aspects of the affected tooth appeared healthy and of normal physical development for were reduced 1 mm on each side to enhance esthetics and his age. There was no reported history of orofacial trauma. to create a space for eruption of the left lateral incisor. The Intraoral examination revealed gingivitis in the anterior notch in the crown was restored with composite resin. region. The occlusion was a Class I molar relationship. In The patient was scheduled to complete reduction of the this mixed dentition, the following permanent teeth were talon cusp on 2 consecutive appointments of 6 to 8 weeks erupted: the first molars, the maxillary central incisors and apart to allow deposition of reparative dentin for pulpal the mandibular incisors. The maxillary central incisors protection and to avoid pulp exposure. Meanwhile, a were rotated, and the left central incisor was labially sectional fixed orthodontic appliance was implemented for displaced, with medial diastema measuring 5.3 mm alignment of the maxillary central incisors and reduction of (Fig. 1). the medial diastema. After 2 sessions, the talon cusp was The maxillary left central incisor had a large and bifid essentially removed, without exposing the pulp or compro- crown with talon cusp on the palatal aspect. The mesiodis- mising the vitality of the tooth (Fig. 4). Three months after tal crown diameter was 2.4 mm larger than the adjacent orthodontic treatment, alignment of the maxillary right right central incisor (11.1 mm vs. 8.7 mm) and 20% larger central incisor was complete and the medial diastema had than its counterpart in the normal population (average been reduced to approximately 2 mm. The maxillary right 8.9 mm, range 7.1 mm to 10.3 mm).18 The tooth was not central incisor was enlarged by placing composite resin on fully erupted, with crown height measuring 8.6 mm. The the mesial aspect of the tooth, yielding a mesiodistal crown crown of the taloned tooth was partially split and had a width of 9.2 mm. Treatment for 5 months resulted in notch on the incisal edge that extended labiolingually to marked improvement in the size, shape and position of the the middle of the crown (Fig. 1). On the palatal aspect, the central incisors as well as enhancement of periodontal crown exhibited a pronounced, well-defined accessory cusp health and appearance (Fig. 5). The patient was scheduled extending from the cementoenamel junction to within for subsequent orthodontic assessment for the palatally 0.5 mm of the incisal edge. The talon cusp was pyramidal erupting maxillary left lateral incisor. in shape and located on the mesial half of the crown, with the tip of the cusp attached to the crown (Fig. 2). The cusp Discussion measured 4.5 mm in length (incisocervically), 3.3 mm in Talon cusp is an odontogenic anomaly of tooth shape width (mesiodistally) and 3.1 mm in thickness (labiolin- that represents the extreme of continuous variation gually). Noncarious developmental grooves were present at progressing from an enlarged cingulum (trace talon) the junction of the talon cusp and the palatal surface of the through a small accessory cusp (semitalon) to a talon cusp.1 tooth. The distal groove was deep and packed with dental Small talon cusps are usually asymptomatic and need no plaque. The affected tooth responded normally to electric treatment. Large talon cusps may cause clinical problems and thermal pulp tests. A periapical radiograph (Fig. 3) including occlusal interference, displacement of the affected showed a V-shaped radiopaque structure superimposed on tooth, irritation of the tongue during speech and mastica- the image of the affected crown, with the point of the “V” tion, carious lesion in the developmental grooves that

264 May 2001, Vol. 67, No. 5 Journal of the Canadian Dental Association An Unusual Case of Talon Cusp on Geminated Tooth

Figure 1: Frontal view on initial presentation showing large, biﬁd and Figure 2: Palatal view demonstrating talon cusp on the geminated left malpositioned geminated maxillary left central incisor associated central incisor projecting from the cingulum and extending almost with wide midline diastema. to the incisal edge. The right central incisor exhibits exaggerated cingulum.

Figure 4: The talon cusp was reduced almost completely after 3 visits at 6- to 8-week intervals without exposing the pulp.

Gemination is a partial cleavage of a single tooth germ resulting in 2 partially or totally separated crowns with enlarged pulp chamber and one root. With gemination, a Figure 3: Periapical radiograph showing talon cusp outlined by two normal number of teeth are maintained. The anomalous white lines representing the enamel, with pulp horn extending to the middle of the cusp. Note the enlarged pulp chamber and the single tooth has a large biﬁd crown and is usually found as an root of the affected tooth. isolated trait, not associated with syndromes. Irrespective of their origin, dental gemination anomalies often give rise to delineate the cusp, pulpal necrosis, periapical pathosis, a number of clinical problems, particularly if the anterior teeth are involved. In our patient, the anomaly caused attrition of the opposing tooth and periodontal problems tooth malalignment, spacing problems, arch asymmetry, due to excessive occlusal forces.1-5 Talon cusps also present unacceptable appearance, periodontal involvement and diagnostic and treatment difficulties. On unerupted tooth, impeded the eruption of the adjacent tooth. the anomalous cusp can radiographically be mistaken for a The treatment of talon cusp involves careful clinical supernumerary tooth or compound odontomas, leading to judgment and review of whether the cusp contains or is unnecessary surgical intervention. This diagnostic problem devoid of a pulp horn. Earlier reports, based on radio- is especially signiﬁcant because approximately 90% of all graphic examination, stated that removal of the cusp would supernumeraries occur in the maxilla and half of these in inevitably lead to pulp exposure that would require the incisor region.19 endodontic treatment.2 However, radiographic tracing of

Journal of the Canadian Dental Association May 2001, Vol. 67, No. 5 265 Hattab, Hazza’a

2. Mellor JK, Ripa LW. Talon cusp: a clinically significant anomaly. Oral Surg Oral Med Oral Pathol 1970; 29(2):225-8. 3. Mader CL. Talon cusp. J Am Dent Assoc 1981; 103(2):244-6. 4. Davis PJ, Brook AH. The presentation of talon cusp: diagnosis, clinical features, associations and possible etiology. Br Dent J 1986; 160(3):84-8. 5. Hattab FN, Yassin OM, al-Nimri KS. Talon cusp — clinical signifi- cance and management: case reports. Quintessence Int 1995; 26(2): 115-20. 6. Sedano HO, Carreon Freyre I, Garza de la Garza ML, Gomar Franco CM, Grimaldo Hernandez C, Hernandez Montoya ME, and others. Clinical orodental abnormalities in Mexican children. Oral Surg Oral Med Oral Pathol 1989; 68(3):300-11. 7. Chawla HS, Tewari A, Gopalakrishnan NS. Talon cusp — a prevalence study. J Indian Soc Pedod Prev Dent 1983; 1(1):28-34. 8. Chen RJ, Chen HS. Talon cusp in primary dentition. Oral Surg Oral Med Oral Pathol 1986; 62(1):67-72. 9. Dankner E, Harari D, Rotstein I. Dens evaginatus of anterior teeth. Figure 5: Appearance of the maxillary incisors after conservative and Literature review and radiographic survey of 15,000 teeth. Oral Surg Oral orthodontic treatment. Med Oral Pathol Oral Radiol Endod 1996; 81(4):472-5. 10. Hattab FN, Yassin OM, Sasa IS. Oral manifestations of Ellis-van Creveld syndrome: report of two siblings with unusual dental anomalies. J Clin Pediatr Dent 1998; 22(2):159-65. the pulpal configuration inside the talon cusp has inherent 11. Grahnen H, Granath LE. Numerical variations in primary dentition difficulties because the cusp is superimposed over the and their correlation with the permanent dentition. Odont Rev 1961; affected tooth crown. Similarly, histological examination of 12:348-57. extracted talon teeth failed to show the presence of a pulp 12. Brook AH. Dental anomalies of number, form and size: their prevalence in British schoolchildren. J Int Ass Dent Child 1974; 5(2):37-53. horn in the talon cusp.20-22 Pitts and Hall removed 3 mm of 13. Buenviaje TM, Rapp R. Dental anomalies in children: a clinical and the anomalous cusp in one visit, without pulp exposure.23 radiographic survey. ASDC J Dent Child 1984; 51(1):42-6. Several times, we have reduced 1.0 mm to 1.5 mm of talon 14. Spouge JD. Oral pathology. St. Louis: C.V. Mosby Co.; 1973. cusp in one appointment without exposing the pulp.1,5 15. Stewart RE. The dentition and anomalies of tooth size, form, struc- However, this does not imply that all talon cusps are devoid ture, and eruption. In: Pediatric Dentistry: scientific foundations and clinical practice. Stewart RE and others, editors. St. Louis: C.V. Mosby of pulp horn. Co.; 1982. Reports describing the treatment of gemination are scant 16. Cullen CL, Pangrazio-Kulbersh V. Bilateral gemination with talon and inconclusive because of the rarity of the condition, cusp: report of case. J Am Dent Assoc 1985; 111(1):58-9. particularly in the permanent dentition. In the present case, 17. al-Omari MA, Hattab FN, Darwazeh AM, Dummer PM. Clinical problems associated with unusual cases of talon cusp. Int Endod J 1999; initial thought was given to reducing tooth structure 32(3):183-90. mesiodistally and placing a composite restoration to give 18. Hattab FN, al-Khateeb S, Sultan I. Mesiodistal crown diameters of the tooth a normal appearance and to prevent plaque accu- permanent teeth in Jordanians. Arch Oral Biol 1996; 41(7):641-5. mulation in the notch of the crown. In addition, ortho- 19. Hattab FN, Yassin OM, Rawashdeh MA. Supernumerary teeth: report of three cases and review of the literature. ASDC J Dent Child dontic consideration was required. 1994; 61(5-6):382-93. Geminated-taloned teeth cause a variety of clinical prob- 20. Natkin E, Pitts DL, Worthington P. A case of talon cusp associated lems that call for early diagnosis. Care should be taken to with other odontogenic abnormalities. J Endod 1983; 9(11):491-5. recognize developmental, periodontal and orthodontic 21. Mader CL, Kellogg SL. Primary talon cusp. ASDC J Dent Child 1985; 52(3):223-6. effects. The patient’s expectation and degree of compliance 22. Salama FS, Hanes CM, Hanes PJ, Ready MA. Talon cusp: a review must also be accurately assessed when determining suitable and two case reports on supernumerary primary and permanent teeth. management. C ASDC J Dent Child 1990; 57(2):147-9. 23. Pitts DL, Hall SH. Talon-cusp management: orthodontic-endodontic considerations. ASDC J Dent Child 1983; 50(5):364-8. Dr. Hattab is consultant and chief, Dental Health Services, Primary Health Care, Ministry of Public Health, Doha, State of Qatar. Dr. Hazza’a is assistant professor, department of oral sciences, faculty of dentistry, Jordan University of Science and Technology, Irbid, Jordan. Correspondence to: Dr. Faiez N. Hattab, Dental Health Services, CDA RESOURCE Primary Health Care, P.O. Box 7604, Doha, State of Qatar. E-mail: [email protected]. C ENTRE The authors have no declared financial interest. The Resource Centre can provide members with any reference listed in this article. CDA members can References contact us at tel.: 1-800-267-6354 or (613) 523-1770, 1. Hattab FN, Yassin OM, al-Nimri KS. Talon cusp in permanent dentition associated with other dental anomalies: review of literature and ext. 2223; fax: (613) 523-6574; e-mail: [email protected]. report of seven cases. ASDC J Dent Child 1996; 63(5):368-76.

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